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sparky4
April 8th, 2016, 01:03 PM
I lost the original bios chip and i cannot find it and i looked and looked but i found no manual or bios rom on the Internet or anything

The mother board is apparently a Gold star Technologies turbo plus 2 board

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I am trying to overclock the turbo mode from 8Mhz to 16 MHz ^^;

modem7
April 8th, 2016, 02:14 PM
I noticed the thick white lines printed around sections of the board. They are the same lines found on the following motherboards:
* X'GOLDEN BOARD
* X'GOLDEN TURBO-BOARD (an 8 MHz board)

Now that I have seen your motherboard, made by Golden Star Technology Inc., I think that there is a good chance that the X'GOLDEN motherboards have the same maker as yours.

In case you would like to try them, the BIOS' for the X'GOLDEN boards are at [here (http://www.minuszerodegrees.net/xt_clone_bios/xt_clone_bios.htm)].

sparky4
April 8th, 2016, 03:59 PM
thanks~ being able to overclock the turbo mode to 16MHz would be dank ^^

modem7
April 8th, 2016, 06:30 PM
I am trying to overclock the turbo mode from 8Mhz to 16 MHz ^^;

thanks~ being able to overclock the turbo mode to 16MHz would be dank ^^
How are you planning to do that?

krebizfan
April 8th, 2016, 06:43 PM
Some of the sources I have seen suggest that the 10 MHz 8088 chips were capable of being clocked much higher. I just wonder if the OP has verified that all the support chips and cards also be pushed that hard.

modem7
April 8th, 2016, 06:52 PM
Some of the sources I have seen suggest that the 10 MHz 8088 chips were capable of being clocked much higher. I just wonder if the OP has verified that all the support chips and cards also be pushed that hard.
And adjustment of timing loops and delays in the BIOS may be required, and possible circuit modification (beyond faster rated chips). Maybe the OP is aware of all of this, and is up for the challenge.

sparky4
April 8th, 2016, 06:58 PM
yes i will modify the custom bios
https://bitbucket.org/sparky4/pcxtbios

the clock rate stuff of 12 is in there

the original tasm file has it
https://bitbucket.org/sparky4/pcxtbios/src/2429f812fa33fb466c3010d2e79d8b01141005ce/pcxtbio0.asm?fileviewer=file-view-default


also i am using a 48MHz crystal for the turbo ^^;

and it dose not boot the system.. which means more modifications are required ^^;

I AM UP FOR THE CHALLANGE!! <3

sparky4
April 9th, 2016, 07:07 AM
Want me to take more photos of the motherboard? ^^;

modem7
April 9th, 2016, 03:15 PM
Want me to take more photos of the motherboard? ^^;
If you are referring to what I have put at [here (http://www.minuszerodegrees.net/xt_clone_bios/Turbo%20Plus%20-2.jpg)], then thanks, but no. That motherboard photo is good enough for the purpose (possible link of X'GOLDEN boards to your board).

sparky4
April 9th, 2016, 03:31 PM
If you are referring to what I have put at [here (http://www.minuszerodegrees.net/xt_clone_bios/Turbo%20Plus%20-2.jpg)], then thanks, but no. That motherboard photo is good enough for the purpose (possible link of X'GOLDEN boards to your board).


ok ^^ it is possible link... hmmm

Chuck(G)
April 9th, 2016, 05:20 PM
Well, back in the day, a few boards used the 9.5MHz variation (2x4.77) as turbo. That should be close enough to 12 for hardware this old, don't you think?

sparky4
April 11th, 2016, 06:34 AM
yeah ^^ when i insert a different crystal

like ones at 32Mhz and 48MHz well the machine dose nothing when i boot it... ^^;

DUPONT
April 12th, 2016, 02:47 PM
I think the problem is with the 8288...must be a 82C88-10 and is not able to give the good timing at 16mhz...
Same problem with the 8284 ; the 82C84 need a different circuit for the Xtal (no 300 ohms resistor and 20pf capacitor to ground instead),and the external clock is limited to 25mhz,good enough for 8mhz turbo,extrem limit 30Mhz for turbo 10Mhz.
the µPD71084C and µPD71088C-10 are not better.
Another problem is that my XT clones run in turbo mode after reset , before checking the turbo switch and selecting the clock source of the 8284..
If they don't crash,the card is running correctly in 4,77 only after switching the clock,but most of the time they crash before and you need try minimum 10 time reset even you select no turbo.
sorry for my poor english

1ST1
April 13th, 2016, 12:47 AM
It's looking very the same as my empty XT mainboard, same layout. But mine has no "Turbo XT" name and manufacturer. I think they are a kind of standard layout, many manufacturer did (except some unimportant details) the same boards.

sparky4
April 13th, 2016, 08:24 AM
I think the problem is with the 8288...must be a 82C88-10 and is not able to give the good timing at 16mhz...
Same problem with the 8284 ; the 82C84 need a different circuit for the Xtal (no 300 ohms resistor and 20pf capacitor to ground instead),and the external clock is limited to 25mhz,good enough for 8mhz turbo,extrem limit 30Mhz for turbo 10Mhz.
the µPD71084C and µPD71088C-10 are not better.
Another problem is that my XT clones run in turbo mode after reset , before checking the turbo switch and selecting the clock source of the 8284..
If they don't crash,the card is running correctly in 4,77 only after switching the clock,but most of the time they crash before and you need try minimum 10 time reset even you select no turbo.
sorry for my poor english

ok i willl look at the chips you mentioned ww

archeocomp
April 13th, 2016, 08:34 AM
I have two "very" fast XTs. One is Commodore PC10-III which is capable to run at 2x4.77MHz. Even faster is Juko XT motherboard, which can run at 10MHz with 8088-1 and at 12MHz with μPD70108 (a NEC 8088 clone).

sparky4
April 13th, 2016, 08:53 AM
found them what do i need to modify on the mother board ? and what new chips do i need to get? ^^

archeocomp
April 13th, 2016, 09:48 AM
You can find schematics of PC10-III here if it helps you.
https://drive.google.com/open?id=0B2TmWnRjWCj2aVNXb1c4Q0VXdzg

DUPONT
April 13th, 2016, 06:29 PM
Good job...
but like i said before,these 8284 and 8288 generate the very critical clock timing for all the other chips..
and there are no higher speed replacement.
the best are M5L8288S or µPD71088C-10 for the system bus controler and µPD71084C-8 for the clock generator
Even you use a 16Mhz processor like a tke NEC V20 µPD10108HCZ-16,it will not work properly without a good timing "earth"

Chuck(G)
April 13th, 2016, 08:21 PM
Given that most XT-class machines operated at 4.77MHz, one has to ask "what's the point?". One thing that can plague you is that software timing loops are common in XT-class software where the clock speed was taken for granted as 4.77MHz. That's one of the reasons that many 286 "turbo" systems have a non-turbo mode. This can create real problems with some peripherals.

I wonder if some systems that used a delay line for RAS/CAS separation on DRAM access will work by simply cranking up the clock.

If you want to fool around with overclocking a slow machine, the 5170 made for a far better platform for that.

Just IMOHO.

sparky4
April 14th, 2016, 05:25 PM
where can i get the faster chips? ^^

sparky4
May 5th, 2016, 11:30 AM
what are the faster chip's names?

sparky4
May 18th, 2016, 09:39 PM
any tips? i failed to over clock it ><

krebizfan
May 18th, 2016, 10:15 PM
Maybe you could describe what you have tried? It could be a bit frustrating to have suggestions to do what you already did.

You may be running in to the problems of board design. Few XT clone boards could handle 12 MHz and even fewer expansion cards worked when the bus was pushed that fast.

Edit: Maybe this web page can help. http://www.malinov.com/Home/sergeys-projects/sergey-s-xt It describes an expansion card holding an XT equivalent system that can run at 13.2 MHz. Very different from your classic motherboard design but may provide some ideas on high speed clock generators and the like depending on how hard you intend to work on the issue.

sparky4
May 24th, 2016, 04:32 PM
ah i installed equivlent chips of the mentioned above and use faster clock crystam from 24Mhz to 32MHz and 48MHz

none of the faster crystals worked

sparky4
May 25th, 2016, 06:06 AM
3134531346 here is the current setup of my attempt to over clock (this works)

jh1523
June 14th, 2016, 05:49 AM
Oh, sorry for being late to this thread, I've been away for a while. I have the same motherboard, see my thread from last year http://www.vcfed.org/forum/showthread.php?48479-XT-clone-built-from-ebay-components
The XT I built around it is pretty tricked-out now, with full 1.44M floppy support, IDE and VGA. I never thought about overclocking though. It's a good board and I'm happy with it.

Best part, I have the board's manual. If you want I can scan and post it.

sparky4
June 17th, 2016, 01:51 PM
Oh, sorry for being late to this thread, I've been away for a while. I have the same motherboard, see my thread from last year http://www.vcfed.org/forum/showthread.php?48479-XT-clone-built-from-ebay-components
The XT I built around it is pretty tricked-out now, with full 1.44M floppy support, IDE and VGA. I never thought about overclocking though. It's a good board and I'm happy with it.

Best part, I have the board's manual. If you want I can scan and post it.

please do!!

jh1523
July 3rd, 2016, 10:59 AM
please do!!

Sorry didn't see the reply until today. I don't come here often. I will when I get back from vacation (I'm currently away from home and won't return until the 3rd week of July).

abandonware
July 7th, 2016, 06:46 AM
Hello, it looks like this motherboard https://th99.bl4ckb0x.de/m/U-Z/33657.htm

sparky4
July 7th, 2016, 08:36 AM
Hello, it looks like this motherboard https://th99.bl4ckb0x.de/m/U-Z/33657.htm

ah~ thats very close to it~

ok

jh1523
October 4th, 2016, 06:28 AM
I'm uploading the manual in the original thread http://www.vcfed.org/forum/showthread.php?48479-XT-clone-built-from-ebay-components/page6